Connectors that are terminated to the ends of electrical cables and mate with mating connectors that are located on fixed panels of electrical equipment are usually keyed so that a cable connector cannot be inadvertently mated to the wrong panel connector. This is especially important when there are several cable connectors mated to somewhat closely adjacent panel connectors, all of which are similar in size and appearance and where the cable connectors must be frequently removed for cleaning or other reasons, such as when interconnecting to other equipment. Since there are a limited number of unique keying arrangements possible, occasionally two panel connectors having the same keying arrangement will be installed in relatively close proximity on the same panel. A problem therefore exists in that there is a likelihood of an inadvertent mismating of these two connectors.